This disclosure is directed toward power machines. More particularly, this discussion is directed toward power machines with lift arms that are capable of carrying a work implement as well as systems and methods for positioning the work implement by controlling the position of the lift arms. Power machines, and more particularly, loaders, have long had lift arms that can carry work implements such as buckets and the like for performing various work tasks. Operators of these machines can advantageously manipulate lift arms carrying such implements to perform various tasks. Not only would an operator have the ability to manipulate the position of the lift arms (known generally as a lift operation), but also to manipulate a position of the work implement with respect to the lift arm (known generally as a tilt operation).
One example of such a task is a digging and loading operation, where an operator may be digging soil with a bucket and then dumping the soil in a truck bed. To perform this task, the operator will have to position the implement via lift and tilt operations to place the bucket in a position to dig soil and then position the implement again to dump the soil into a truck bed. Repetitive positioning of the implement requires that the operator repeatedly concentrate on precisely controlling the lift arm to place the bucket in the dig position and the dump position.
In addition, raising and lowering the lift arms of a power machine and particularly a loader by manipulating one or more lift arm actuators can change the angle of the implement with respect to gravity over the lift arm path of certain loaders. That is, if the path of the lift arm is not perfectly vertical, simply raising or lowering the lift arm will change the orientation of the implement with respect to gravity unless the implement is also tilted with respect to the lift arm. This can cause material contained within a bucket, for example, to spill out during the raising or lowering process. This relationship between an implement and gravity can be further changed if the power machine is travelling over uneven terrain.